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When to Plant Rue in Walla Walla County, WA

Rue is a bitter, aromatic perennial herb with bluish-green foliage used historically in medicine and as a pest deterrent. Handle with care as its sap can cause skin irritation.

Walla Walla County, Washington is in USDA Zone 6b. The average last spring frost is April 20 and the first fall frost is October 15, giving you a growing season of approximately 178 days.

At an elevation of 3,151 feet, Walla Walla County receives approximately 23.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85ยฐF, providing good warmth for Rue during the growing season.

Walla Walla County, WA (Zone 6b) Moderate season
178 days
Last Spring Frost April 20
178 growing days
First Fall Frost October 15

Walla Walla County Soil Profile

Soil Type

Silt Loam

Soil pH

5.2-6.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (47 days to spare)
Transplant: Apr 10 🍅 Harvest: Jun 19 – Aug 21
Recommended (50%) ✓ Fits season (38 days to spare)
Transplant: Apr 27 🍅 Harvest: Jul 6 – Sep 7
Safe Start (90%) ✓ Fits season (37 days to spare)
Transplant: May 21 🍅 Harvest: Jul 30 – Oct 1

Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.6″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Rue needs ~1,100 GDD — county provides 2,447 GDD Excellent fit

Rue Planting Timeline โ€” Walla Walla County, WA

Rue Planting Calendar

Activity When Date Range
Transplant Outdoors April 27 Apr 27 โ€“ May 11
Harvest July 6 Jul 6 โ€“ Sep 7

Plant 0.5" deep ยท 8" apart ยท Rows 12" apart

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April Transplant Outdoors
May Transplant Outdoors
June โ€”
July Harvest
August Harvest
September Harvest
October โ€”
November โ€”
December โ€”

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Low โ€” drought tolerant

Days to Maturity

70โ€“90 days

Soil pH

6 โ€“ 7.5

USDA Zone

Zone 6b

Growing Season

178 days

Growing Tips for Walla Walla County

Start seeds indoors or direct sow. Plant in well-drained soil. Wear gloves when handling as sap can cause phytophotodermatitis. Prune in early spring.

Companion Planting

Good Companions

Avoid Planting Near

  • Basil
  • Sage

Level Up Your Garden

Frequently Asked Questions

When should I plant Rue in Walla Walla County, WA?

Walla Walla County is in Zone 6b with an average last frost of April 20. Plan your Rue planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Walla Walla County, WA?

Walla Walla County, Washington is in USDA Hardiness Zone 6b. The average last spring frost is April 20 and first fall frost is October 15.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Walla Walla County gardeners in Zone 6b organize planting dates, track what's growing, and never miss a planting window.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Walla Walla County, WA. Local conditions may vary. Last updated: April 2026.